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\title{Emergency Call Services for SIP-based Internet Telephony}
\author{H. Schulzrinne}
\shorttitle{Emergency Calling}
\filename{draft-schulzrinne-sip-911-02}
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\expires{December 2002}
\address{Columbia U.}
\pubdate{\today}
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\begin{document}
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\begin{abstract}
If Internet Telephony is to offer a full replacement for traditional
telephone services, it needs to provide emergency call services.  In the
United States, emergency calls are known as 911 services, based on the
number dialed.  

Current emergency services perform two functions: they route the call to
an appropriate emergency call center with a single, location-independent
identifier and they allow the emergency call center to determine the
location, to varying degrees of accuracy, of the caller.

Both of these features are made more difficult by the temporary nature
of IP addresses, the large number of ISPs and their lack of legal
responsibility for emergency services and the ability of many Internet
terminals to be connected to the Internet at different locations.  This
note explores some of the requirements and design choices, both for
interoperation with traditional PSTN-based emergency call centers as
well as SIP-aware emergency call centers.
\end{abstract}

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\section{Acknowledgements}

Matthew Cannon, Dave Devanathan, Mark Handley, Brian Rosen, Jonathan
Rosenberg and Henry Sinnreich participated in an earlier discussion on
this topic.  Jonathan Rosenberg and John Stanaway provided helpful
comments on this draft.

\section{Authors' Addresses}
\begin{flushleft}
Henning Schulzrinne\\
Dept. of Computer Science\\
Columbia University\\
1214 Amsterdam Avenue\\
New York, NY 10027\\
USA\\
electronic mail: {\sf schulzrinne@cs.columbia.edu}
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